This invention relates to packaging doides, and more particularly to hermetic leadless packaging of p-n, Schottky, and other planar diodes. This concept could also be extended to three lead packages for devices like transistors.
It is known to place p-n, Schottky, and other planar diodes in hermetic packages to facilitate their use. However, the known packages have various disadvantages due to large parasitic capacitance, inductance, and thermal resistance caused by their bulky multilayer construction, especially in high frequency circuit applications. Such packages use copper for diode contacts which has a poor thermal match to the diode, or use alloys for the diode which contain Ni and therefore exhibit significant resistance and inductance. A poor thermal match results in the solder connection between the contact and the diode separating or the diode cracking during temperature cycling.
It is generally known to use C- or S-shaped spring contacts to provide for stress relief in the vertical direction, but if there is not a good thermal match between the contact metal and the diode semiconductor, there is a possibility of diode delamination or cracking. The term "delamination" used hereinafter refers to the breaking loose of the connection between the contact and the diode which may occur regardless of how the connection (ohmic contact) is made to the diode.